Apparatus for the On-line GC Determination of Hydrocarbon Solubility in Water:  Benzene and Cyclohexane from 70 °C to 150 °C

It is proposed in this paper to extend the original group contribution method PPR78 to systems containing water, by combining it to the Cubic–Plus–Association (CPA) equation of state (EoS). Applying simple geometric combination rules, the binary interaction parameter kij(T) can be calculated from interaction parameters between hydrocarbon groups and water. This model, called the GC–PR–CPA is applied to predict hydrocarbons – water mutual solubilities over a wide temperature and pressure range, depending on available literature data. Group interaction parameters, here CH4, C2H6, CH3, CH2, CH, C, CHaro, CH2,cyclic, CHcyclic/Ccyclic, C2H4, CH2,alkene/CHalkene with H2O have been defined with solubility data. Predictions of the developed model have been validated against independent solubility data as well as water content in hydrocarbon rich phase. Predictions of the new model are in good agreement for light and medium hydrocarbons; however, some deviations are observed for heavier hydrocarbons.

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“…Cyclohexane (▴) and (●), and methylcyclohexane (♦) solubility in water at 0.1 MPa. Dashed lines: SRK‐CPA EoS with adjusted k ij .…”

Section: Resultsmentioning

confidence: 99%

Hydrocarbons – water phase equilibria using the CPA equation of state with a group contribution method

2014

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“…To achieve a rapid equilibrium, a magnetic stirring alternative movement system was used to mix the water and the hydrocarbon. 1 This system works with an induction motor (25 W, 1200 rpm Sungshin P and Ind, Korea) coupled with a speed reducer (15/1) to avoid emulsions. The sampling procedure, in the equilibrium time, was realized by using the solid-phase extraction method.…”

Section: Methodsmentioning

confidence: 99%

Solubilities of Alkylcyclohexanes in Water from 30 °C to 180 °C

2004

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A solid-phase extraction method has been developed for measuring low solubilities of hydrocarbons in water. The solubilities in water of methylcyclohexane, ethylcyclohexane, trans-1,2-dimethylcyclohexane, and a mixture of 1,2-dimethylcyclohexane isomers (respectively, 89.3 mol % and 10.7 mol % of the cis and trans isomers) were determined at temperatures ranging from (30 to 180)°C. At 30°C, the mole fraction solubility is (2.96 ( 0.03) × 10 -6 for methylcyclohexane, (0.699 ( 0.007) × 10 -6 for ethylcyclohexane, and (0.80 ( 0.02) × 10 -6 for trans-1,2-dimethylcyclohexane. The mole fraction solubility is (1.09 ( 0.01) × 10 -6 and (0.91 ( 0.01) × 10 -6 , respectively, for cis-1,2-dimethylcyclohexane and trans-1,2-dimethylcyclohexane (from the mixture). Temperature effect on solubility in water for ethylcyclohexane and for the dimethylcyclohexanes is very similar. Increasing the temperature from (30 to 180)°C increases the solubilities by a factor of approximately 40. IntroductionWater is continuously present during the fluid-reservoir formation and the exploitation of oil and gas reservoirs. Also, knowledge of water-hydrocarbon phase behavior is of tremendous interest in the environmental sciences and in the chemical and petroleum industries.There is a large amount of solubility data in the literature, and nearly all available data are at ambient conditions, or these data are in poor agreement.In a previous paper, 1 we reported solubility measurements in water for benzene and cyclohexane over the temperature range of (70 to 150)°C. A static apparatus has been designed and constructed for these determinations. It allows for the on-line analysis by gas chromatography of the hydrocarbon saturated aqueous phase in equilibrium. But the solubility of alkanes and alkylcyclohexanes in water is lower than the solubility of aromatics or cyclohexane. The on-line method previously described and used 1 was not adapted and was modified. 2 Water saturation is still performed using the static method, but the sampling procedure is accomplished using the solidphase extraction method. 3 Trace hydrocarbon saturated water is trapped in a C18 column and then eluted by methanol. Methanol + hydrocarbon solutions are analyzed by gas-chromatography flame-ionization detection (GC-FID) using an internal standard calibration method.The present work reports the solubility in water of methylcyclohexane, ethylcyclohexane, trans-1,2-dimethylcyclohexane, and of a mixture of 1,2-dimethylcyclohexane isomers (cis + trans) at temperatures ranging from (30 to 180)°C.

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“…The different parts of the sampler are displayed in the axial cross sectional view presented in Figure 9. The screw (1) allows adjustment of the force of the spring (8) acting on the pinholder (15), by moving the force transmitter part (7), to achieve perfect sealing between the titanium pin (16) and capillary (21) whatever the sampling pressure. A differential screw (2) and a stroke adjustment screw (3) permits fine adjustment of the pin-holder stroke and consequently of the sample sizes.…”

Section: Equipment and Materialsmentioning

confidence: 99%

“…These results seems to be within the experimental uncertainty by observing the literature values presented at 423.15 K in Figure 15. 20,21 4.3. Solubility of 2-Methylfuran in Water.…”

Section: Solubility Of Cyclohexane In Water Andmentioning

confidence: 99%

Design of Equilibrium Cells for Phase Equilibria and PVT Measurements in Large Ranges of Temperatures and Pressures. I. Vapor–Liquid–Liquid Equilibria

et al. 2016

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Acquiring accurate experimental thermodynamic data is very useful for the development of models and chemical processes. Although there are plenty of data in the scientific literature, there are still many missing. In fact, many of the easier measurements have been made, and far more of the remaining ones deal with either complex systems or extreme conditions. Clearly new adequate equipment for acquiring such data are welcome. For these purposes, advice coming from several decades of equipment design experience are exposed herein. After defining the aim pursued and consequently the type of desired thermodynamic quantity, it is necessary to take into account all physical and chemical constraints: viscosity, density, corrosive power of studied chemical systems, temperature, pressure together with other important points such as miniaturization, efficient stirring, avoiding both dead volume and polymer sealing. The other aim of this paper is to present a high temperature and high pressure apparatus capable of measuring the phase equilibria of systems exhibiting vapor–liquid–liquid behavior. The apparatus designed and built consists mainly of an equilibrium cell (70 cm3), novel high temperature, and high pressure samplers and a gas chromatograph. A detailed description of the apparatus is presented. Preliminary measurements are presented for propane in water, cyclohexane in water, and water in cyclohexane up to 498.8 K. In addition the solubility of 2-methylfuran in water up to 413 K and 1548 kPa was measured.

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Apparatus for the On-line GC Determination of Hydrocarbon Solubility in Water: Benzene and Cyclohexane from 70 °C to 150 °C

Cited by 19 publications

References 7 publications

Hydrocarbons – water phase equilibria using the CPA equation of state with a group contribution method

Hydrocarbons – water phase equilibria using the CPA equation of state with a group contribution method

Solubilities of Alkylcyclohexanes in Water from 30 °C to 180 °C

Design of Equilibrium Cells for Phase Equilibria and PVT Measurements in Large Ranges of Temperatures and Pressures. I. Vapor–Liquid–Liquid Equilibria

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